OptSCORE: Self-optimised efficiency, security and resilience for active replication

可靠的资讯科技服务对现代社会至为重要。联网系统必须解决与可用性、安全性和安全需求相关的大量问题。复制是解决这些问题的一种基本方法。云计算、面向服务的体系结构和多核CPU因其高度的并行性和动态性而挑战现有的复制体系结构。OptSCORE项目的目标是找到新的解决方案来应对这些挑战。为此，我们将重点放在状态机复制(SMR)作为核心架构。基于SMR的复制服务提供高可用性和强一致性，不仅可以容忍崩溃，甚至可以容忍拜占庭故障。在第一个项目阶段确定了确定性调度和组通信系统的配置参数后，我们的下一个目标是为任何给定的应用找到这些参数的配置，以便吞吐量和/或延迟成为最佳。挑战在于可能的参数组合及其相互依赖的复杂性。我们计划使用组合优化方法以及机器学习来寻找最佳配置。此外，我们希望使SMR系统能够在运行时动态地自适应复制的应用程序的需求。此外，我们希望在SMR系统中使用入侵检测机制来增强固有的错误屏蔽，以集成纠错方法，特别是在拜占庭容错安装中。全面的安全分析将导致对SMR系统和前述优化机制的攻击。研究合适的防御机制是本研究项目的主要目标。几个进一步优化的策略是对这些努力的补充。特别是，我们将尝试研究和解决以下问题：CRDT是否允许通过使用部分而不是完全有序的组播来提高效率，而不会损失较强的一致性？如何防止速度较慢的副本降低整个系统的速度？如何使必要的检查点机制与请求的并发处理一起工作？本项目的预期研究成果将大大有助于提高高可用和可靠服务的效率，并简化和加速它们的配置。

Reliable IT services are essential for a modern society. Networked systems have to solve a multitude of problems pertaining to availability, safety and security demands. Replication is one basic method to tackle these problems. Cloud computing, service-oriented architectures and multicore CPUs challenge established replication architectures due to their high parallelism and dynamicity.The goal of the OptSCORE project is to find new solutions for these challenges. To this end, we focus on State-Machine Replication (SMR) as the core architecture. SMR-based replicated services provide high availability coupled with strong consistency, and can tolerate not only crashes but even Byzantine faults.After the first project phase determined configuration parameters for deterministic scheduling and group communication systems, our next goal is to find configurations of these parameters for any given application, so that throughput and/or latency become optimal. The challenge lies in the complexity of possible parameter combinations and their interdependencies. We plan to use combinatorial optimisation methods as well as machine learning for finding optimal configurations. Additionally, we want to enable SMR systems to dynamically self-adapt to a replicated application's demands during runtime.Furthermore, we want to augment the inherent fault masking in SMR systems with intrusion-detection mechanisms to integrate error correction methods, especially in Byzantine fault-tolerant installations. A comprehensive security analysis will yield attacks both on SMR systems in general and on the aforementioned optimisation mechanisms. Researching suitable defensive mechanisms is a main goal of this research project.Several further optimisation strategies complement these efforts. In particular, we will try to research and solve the following problems: Do CRDTs allow to improve efficiency by employing partially as opposed to totally ordered multicasts, without losing strong consistency? How can a slow replica be prevented from slowing down the entire system? How can the necessary checkpointing mechanisms be made to work with concurrent processing of requests?The expected research results of this projects will significantly contribute to making highly-available and reliably services more efficient and to simplify and accelerate their configuration.